1. Field of the Invention
The invention relates to a medical device, more particularly a filter, a cannula, a catheter or an implant, of plastic or plastic-coated metal or glass, which can be used inside or outside the human body to fix, and thereby to render harmless, disease-causing microorganisms, particularly viruses, bacteria, and fungi, as well as pathogenic metabolic products, toxins, lipoid substances, and drugs. The invention relates in particular to filters for the separation of disease-causing microorganisms, especially viruses, bacteria, and fungi, as well as pathogenic metabolic products, lipoid substances, toxins, and drugs from blood, as well as cannulas, catheters, and implants that can be introduced into the human body without the risk of infection.
2. Description of the Prior Art
Unexamined West German Patent Application DE-OS 32 28 849 discloses a medical device to be introduced into the body and having a coating which releases microbicidal metal ions. The metal ions are gold, silver, and copper ions.
With devices to be introduced into the human body, e.g., probes, it is also well known in the art to treat the surface of the probes with iodine compounds to reduce the risk of infection.
However, the prior art processes have proved to be inadequate in practice, because the applied agents such as precious metal ions, iodine compounds, or antibiotics are released from the coated material and thus the risk of infection is reduced only during a brief period. Also, any microorganisms that may be present react metabolically with the released substances, so that resistances and the like may be developed. In addition to the risk of infection, the formation of a fibrin layer on the surface of intravasal catheter has a deleterious effect on catheters to be introduced into the body. The proposed solution, i.e., to coat intravasal catheters with heparin in order to avoid the usual fibrin deposits, has likewise proved unsuccessful.
The increasing development of multiple resistance and the high financial cost associated therewith call for a new protective system. Therefore, catheters, cannulas, or implants that can remain in the body for long periods of time without the risk of infection are desired.
Furthermore, efforts have been made for a long time in the medical field to develop treatment methods for highly toxic, viral or bacterial infectious diseases, such as AIDS, hepatitis A, hepatitis B, non-A, non-B hepatitis, tetanus, and genetically conditioned metabolic disorders, e.g., phenylketonuria, or other intoxications such as, for example, with digitalis glycosides or barbiturates. Success, however, has been very limited. Interferon has been used as an established agent against viral diseases, but the efficacy of interferon treatment is very limited, because the spectra of the various interferons and the organ specificities thereof differ considerably.
Despite substantial outlays of material and work involved, the therapeutic results to date have also been limited with respect to bacterial diseases, such as tetanus, genetically conditioned metabolic disorders such as phenylketonuria, or intoxications, e.g. with digitalis glycosides or barbiturates.
Accordingly, a simple method was desired by which the disease-causing viruses, bacteria, fungi, pathogenic metabolic products, lipoid substances (particularly lipids), and drugs can be removed from, or filtered out, of the blood. However, the treatment method is to be designed such that the disease-causing substances or other substances, if they can be removed by filtration, do not remain in the blood as an antigen-antibody complex.
Accordingly, the invention has as its object the development of a medical device, particularly cannulas, catheters, and implants as well as filters made of plastic or plastic-coated metal or glass, by means of which disease-causing microorganisms, particularly viruses, bacteria, and fungi as well as pathogenic metabolic products, toxins, lipoid substances (especially lipids), and drugs in blood, particularly human blood, can be fixed inside or outside the human body in such a way that the infections caused thereby can be prevented with assurance, or that these undesirable substances can be reliably removed from the blood without risk.